Akka.Persistence.Azure

Akka.Persistence implementation that uses Windows Azure table and blob storage.

Configuration

Easy Mode: Using Akka.Hosting

Akka.Hosting can make configuring Akka.Persistence.Azure trivially easy and HOCON-less.

First, install the Akka.Persistence.Azure.Hosting NuGet package:

PS> install-package Akka.Persistence.Azure.Hosting

Next, add the WithAzurePersistence method calls to your AkkaConfigurationBuilder (from Akka.Hosting):

var conn = Environment.GetEnvironmentVariable("AZURE_CONNECTION_STR");
var host = new HostBuilder()
    .ConfigureServices(collection =>
    {
        collection.AddAkka("MyActorSys", builder =>
        {
          // enables both journal and snapshot store
            builder.WithAzurePersistence(conn);
            builder.StartActors((system, registry) =>
            {
                var myActor = system.ActorOf(Props.Create(() => new MyPersistenceActor("ac1")), "actor1");
                registry.Register<MyPersistenceActor>(myActor);
            });
        });
    }).Build();

await host.StartAsync();
return host;

You can also call the following methods to activate the journal / snapshot stores independently:

• WithAzureTableJournal
• WithAzureBlobsSnapshotStore

Using Azure.Identity.DefaultAzureCredential With Akka.Hosting

var host = new HostBuilder()
    .ConfigureServices(collection =>
    {
        collection.AddAkka("MyActorSys", builder =>
        {
            var credentials = new DefaultAzureCredential();
            
            // Add the journal table
            builder.WithAzureTableJournal(
                serviceUri: new Uri("https://{account_name}.table.core.windows.net"),
                defaultAzureCredential: credentials);
            
            // Add the snapshot-store blob container
            builder.WithAzureBlobsSnapshotStore(
                serviceUri: new Uri("https://{account_name}.blob.core.windows.net"),
                defaultAzureCredential: credentials);
            
            builder.StartActors((system, registry) =>
            {
                var myActor = system.ActorOf(Props.Create(() => new MyPersistenceActor("ac1")), "actor1");
                registry.Register<MyPersistenceActor>(myActor);
            });
        });
    }).Build();

await host.StartAsync();
return host;

Using Configurable Setup Class With Akka.Hosting

WithAzureTableJournal and WithAzureBlobsSnapshotStore have an overload that allows you to use AzureTableStorageJournalSetup and AzureBlobSnapshotStoreSetup class respectively that allows you to configure all settings that are available in the HOCON settings. These setup classes also allows you to set Azure.Identity.DefaultAzureCredential programmatically.

There are two overload types that you can use, one by passing the Setup class instance directly, and the other using a delegate. Both have the same result at the end, use one that fits your programming style the best.

var host = new HostBuilder()
    .ConfigureServices(collection =>
    {
        collection.AddAkka("MyActorSys", builder =>
        {
            var credentials = new DefaultAzureCredential();
            
            // Programatically setup the journal table using delegate
            builder.WithAzureTableJournal(setup => 
            {
                setup.TableName = "myazuretable";
                setup.ServiceUri = new Uri("https://{account_name}.table.core.windows.net");
                setup.DefaultAzureCredential = credentials;
                // Optional TableClientOptions
                setup.TableClientOptions = new TableClientOptions(); 
            });
            
            // You can also programatically pass in a Setup instance
            /*
            builder.WithAzureTableJournal(new AzureTableStorageJournalSetup
            {
                TableName = "myazuretable",
                ServiceUri = new Uri("https://{account_name}.table.core.windows.net"),
                DefaultAzureCredential = credentials,
                // Optional TableClientOptions
                TableClientOptions = new TableClientOptions() 
            });
            */
            
            // Programatically setup the snapshot-store blob container using delegate
            builder.WithAzureBlobsSnapshotStore(setup => {
                setup.ContainerName = "myAzureBlobContainer";
                setup.ServiceUri = new Uri("https://{account_name}.blob.core.windows.net");
                setup.DefaultAzureCredential = credentials;
                // Optional BlobClientOptions
                setup.BlobClientOptions = new BlobClientOptions(); 
            });
            
            // You can also programatically pass in a Setup instance
            /*
            builder.WithAzureBlobsSnapshotStore(new AzureBlobSnapshotStoreSetup {
                ContainerName = "myAzureBlobContainer",
                ServiceUri = new Uri("https://{account_name}.blob.core.windows.net"),
                DefaultAzureCredential = credentials,
                // Optional BlobClientOptions
                BlobClientOptions = new BlobClientOptions() 
            });
            */
            
            builder.StartActors((system, registry) =>
            {
                var myActor = system.ActorOf(Props.Create(() => new MyPersistenceActor("ac1")), "actor1");
                registry.Register<MyPersistenceActor>(myActor);
            });
        });
    }).Build();

await host.StartAsync();
return host;

Custom Mode: HOCON

Here is a default configuration used by this plugin: https://github.com/petabridge/Akka.Persistence.Azure/blob/dev/src/Akka.Persistence.Azure/reference.conf

You will need to provide connection string and Azure Table name for journal, and connection string with container name for Azure Blob Store:

# Need to enable plugin
akka.persistence.journal.plugin = akka.persistence.journal.azure-table
akka.persistence.snapshot-store.plugin = akka.persistence.snapshot-store.azure-blob-store

# Configure journal
akka.persistence.journal.azure-table.connection-string = "Your Azure Storage connection string"
akka.persistence.journal.azure-table.table-name = "Your table name"

# Configure snapshots
akka.persistence.snapshot-store.azure-blob-store.connection-string = "Your Azure Storage connection string"
akka.persistence.snapshot-store.azure-blob-store.container-name = "Your container name"

Using Azure.Identity.DefaultAzureCredential Through Programmatic Setup

Since there is no way to pass in DefaultAzureCredential through HOCON settings, this has to be done programatically using Setup classes.

// Need to enable plugin
var config = ConfigurationFactory.ParseString(@"
akka.persistence.journal.plugin = akka.persistence.journal.azure-table
akka.persistence.snapshot-store.plugin = akka.persistence.snapshot-store.azure-blob-store");

var credentials = new DefaultAzureCredential();
var setup = BootstrapSetup.Create()
    .WithConfig(config)
    // Add DefaultAzureCredential to snapshot-store using Setup class
    .And(new AzureBlobSnapshotSetup 
    {
        ServiceUri = new Uri("https://{account_name}.blob.core.windows.net"),
        DefaultAzureCredential = credentials,
        BlobClientOptions = new BlobClientOptions() // Optional
    })
    // Add DefaultAzureCredential to journal table using Setup class
    .And(new AzureTableStorageJournalSetup 
    {
        ServiceUri = new Uri("https://{account_name}.table.core.windows.net"),
        DefaultAzureCredential = credentials,
        TableClientOptions = new TableClientOptions() // Optional
    });

var myActorSystem = ActorSystem.Create("myActorSystem", setup);

Local development mode

You can turn local development mode by changing these two settings:

akka.persistence.journal.azure-table.development = on
akka.persistence.snapshot-store.azure-blob-store.development = on

When set, the plugin will ignore the connection-string setting and uses the Azure Storage Emulator default connection string of "UseDevelopmentStorage=true" instead.

Configuring snapshots Blob Storage

Auto-initialize blob container

Blob container auto-initialize behaviour can be changed by changing this flag setting:

# Creates the required container if set
akka.persistence.snapshot-store.azure-blob-store.auto-initialize = on

Container public access type

Auto-initialized blob container public access type can be controlled by changing this setting:

# Public access level for the auto-initialized storage container. 
# Valid values are "None", "BlobContainer" or "Blob"
akka.persistence.snapshot-store.azure-blob-store.container-public-access-type = "None"

DefaultAzureCredential

Azure.Identity DefaultAzureCredential can be used to configure the resource by using AzureBlobSnapshotSetup. When using DefaultAzureCredential, the HOCON 'connection-string' setting is ignored.

Example:

var blobStorageSetup = AzureBlobSnapshotSetup.Create(
  new Uri("https://{account_name}.blob.core.windows.net"), // This is the blob service URI
  new DefaultAzureCredential() // You can pass a DefaultAzureCredentialOption here.
                               // https://docs.microsoft.com/en-us/dotnet/api/azure.identity.defaultazurecredential?view=azure-dotnet
);

var bootstrap = BootstrapSetup.Create().And(blobStorageSetup);
var system = ActorSystem.Create("actorSystem", bootstrap);

Using the plugin in local development environment

You can use this plugin with Azure Storage Emulator in a local development environment by setting the development flag in the configuration file:

akka.persistence.journal.azure-table.development = on
akka.persistence.snapshot-store.azure-blob-store.development = on

you do not need to provide a connection string for this to work, it is handled automatically by the Microsoft Azure SDK.

Building this solution

To run the build script associated with this solution, execute the following:

Windows

c:\> build.cmd all

Linux / OS X

c:\> build.sh all

If you need any information on the supported commands, please execute the build.[cmd|sh] help command.

This build script is powered by FAKE; please see their API documentation should you need to make any changes to the build.fsx file.

Conventions

The attached build script will automatically do the following based on the conventions of the project names added to this project:

• Any project name ending with .Tests will automatically be treated as a XUnit2 project and will be included during the test stages of this build script;
• Any project name ending with .Tests will automatically be treated as a NBench project and will be included during the test stages of this build script; and
• Any project meeting neither of these conventions will be treated as a NuGet packaging target and its .nupkg file will automatically be placed in the bin\nuget folder upon running the build.[cmd|sh] all command.

DocFx for Documentation

This solution also supports DocFx for generating both API documentation and articles to describe the behavior, output, and usages of your project.

All of the relevant articles you wish to write should be added to the /docs/articles/ folder and any API documentation you might need will also appear there.

All of the documentation will be statically generated and the output will be placed in the /docs/_site/ folder.

Previewing Documentation

To preview the documentation for this project, execute the following command at the root of this folder:

C:\> serve-docs.cmd

This will use the built-in docfx.console binary that is installed as part of the NuGet restore process from executing any of the usual build.cmd or build.sh steps to preview the fully-rendered documentation. For best results, do this immediately after calling build.cmd buildRelease.

Release Notes, Version Numbers, Etc

This project will automatically populate its release notes in all of its modules via the entries written inside RELEASE_NOTES.md and will automatically update the versions of all assemblies and NuGet packages via the metadata included inside common.props.

If you add any new projects to the solution created with this template, be sure to add the following line to each one of them in order to ensure that you can take advantage of common.props for standardization purposes:

<Import Project="..\common.props" />